Shanti Pereira lives her life to the sound of a gun. It goes off and so does she. In her world, time is precious, for her life is measured in tiny slices of a second. Every millisecond matters and every fraction shaved off her timing is a triumph.
Like many athletes, Pereira’s form stagnated. Improvement eluded her from June 2015 until May 2022. Then, she transformed.
It has been a staggering transformation and the primary factor has been Pereira’s steadfastness and her energising partnership with her new coach Luis Cunha. Steadily, they have gone faster.
Scroll on to see and hear how she has improved, in her own words.
Head below waist
Knee-driven
Straight line from head to toe
45° shin angle
Knee ahead
of ankle
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Posture is key during the start. To propel her body forward, Pereira’s head has to be below the waist.
A good start involves complex mechanics, but Cunha preaches a few things to Pereira.
The first thing the coach wants is for her to drive her knees at the start.
He also wants her torso to be leaning forward in a straight line from the head to the toe. The angle of the shin should be at 45 degrees. The shoulders should be on top of the knees.
Ideally, the knee should be positioned in front of the ankle throughout the race.
There are two changes Pereira has made to her start that have allowed her to go even faster.
3 steps from the starting line
3.5 steps from the starting line
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Cunha got Pereira to put her left leg half a step back on the starting block.
This is so that her knees and hips are better angled to produce more force.
Crumpled paper
Cycling motion
Forward motion
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Cunha takes pieces of crumpled paper and places them just in front of Pereira’s feet.
During her start, Pereira’s initial step – which had a cycling motion – was too high and so she was braking when her foot landed.
As she takes her first stride, Cunha wants her foot to be closer to the ground to ensure forward motion. It is why he places the paper there.
If she steps over the paper, she is erring. If she kicks it over, she is doing it right.
This change allows her legs to produce force in the right direction and ensures she is prepared early for the next step.
156°-160°
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Pereira has to maintain a specific posture to ensure that she will hit her maximum speed.
She should scissor her thighs to minimise the knee gap at touchdown. The angle of her leg that is anchored to the ground has to be about 156 to 160 degrees.
While the legs are vital, the upper body has to provide support. Her arms have to be perfectly synchronised with her leg movements.
Cunha is trying to help Pereira find the ideal position where her knee is positioned in front of the ankle throughout the sprint. But this is very hard to do.
The primary change Pereira has made for the middle section of the race is learning how to brake less.
Knees are mostly in line
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This video demonstrates Pereira’s point about braking. When her leg is on the ground and her knees are in line, it tells her that she is braking less.
This allows her to stride freely and hit her top speed.
Can you guess Pereira’s maximum stride length during the fastest part of the 100m race?
Pereira’s maximum stride length is roughly 227cm.
Pereira’s stride today is about 20cm longer than it was in 2017.
Time determined from torso position
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The finish is possibly the least technical part of the race. There are many versions of the dip and some runners even dive across the line.
The priority is to push her shoulders as far forward as possible. In a photo finish, it is the position of the torso that determines who wins the race.
Cunha has taught Pereira a few key things. To not panic. To maintain the correct form until the last step and keep her head low. And to ensure she times her dip perfectly.
The main change Pereira has made is to actually practise her dip. This paid off during the 100m final at the SEA Games in 2022.
Practice, hopefully, will make perfect.
Because the complicated journey to the Asian Games is not finished yet.
Data is crucial to Pereira’s success but Cunha is careful not to overload her with it.
He makes sense of sport through the numbers he gathers. You see one fluid race, he sees a footrace broken into multiple sections. His world is files and data and his life is a collection of Pereira’s timings, steps taken and flight times. He’s a professor on the track and a student in front of his laptop.
The lean Pereira is the opposite. She is an athlete of instinct who is guided by feel. One might say she’s an artist and Cunha is a scientist.
Their partnership works because the coach does not overload the runner. He passes on information on a need-to-know basis and she trusts him because his method is working. If he says her left foot is weaker, he won’t explain the data that confirms it. He’ll just help her fix it.
Cunha collects data of Pereira’s flight time for each foot. Flight time refers to the time in seconds where both feet are in the air after pushing off on either the left or the right foot.
The data tells Cunha that Pereira’s left foot is consistently in the air longer than her right foot. This could mean one of two things: her right leg is pushing more or her left leg is moving slower.
He also looks at the percentage of difference between the right and left to see by how much and how often the left is slower or weaker than the right.
To visualise this better, he converts this into a bar chart of percentages and notes those that are higher than 10 per cent.
From these findings, he identifies the issue is her left leg moving slower and they have since worked on improving this by strengthening her left quadriceps, potentially making her even faster.
From the High Performance Laboratory at the Singapore Sports Institute to the track, from the Altitude House to the gym, Pereira’s form has been investigated, her races analysed, her muscles toned and her stride examined by high-speed cameras. To her work ethic has been brought the expertise of dieticians, psychologists and biomechanists.
Pereira has run hundreds of miles in practice and they have flown thousands of kilometres in search of her best. This year, she has competed in New Zealand, Australia, Thailand, Germany, Hungary, Switzerland and Cambodia, leaving her footprints across the world.
As at Sept 17, she has five of the top 10 100m timings in Asia in 2023 and eight of the top 10 200m timings.
The 100m might seem a very short race. But Pereira has come a very long way.
How ST developed this story
The Straits Times got an exclusive peek into their world when it spent a day with Pereira and coach Cunha, filming the athlete at the track and at the High Performance Laboratory at the Singapore Sports Institute, and listening to them dissect their craft and explain her improvement.
Both the digital graphics and video teams have put together this interactive to help people understand the science – and art – behind the sprint.
We paired slow-motion videos captured via three different camera angles with the careful biomechanical annotations provided by Cunha. The design teams were able to bring to life the details of how she has improved her run through motion graphics.
Data was obtained from Cunha, the Singapore Sports Institute and the World Athletics Organisation.